KönigsbergKönigsberg (ˈkøːnɪçsbɛʁk, King's mountain) was the historic German and Prussian name of the city that is now Kaliningrad, Russia. It was founded in 1255 on the site of the small Old Prussian settlement Twangste by the Teutonic Knights during the Baltic Crusades. It was named in honour of King Ottokar II of Bohemia, who led a campaign against the pagan Old Prussians, a Baltic tribe. A Baltic port city, it successively became the capital of the State of the Teutonic Order, the Duchy of Prussia and the provinces of East Prussia and Prussia.
KaliningradKaliningrad (kəˈlɪnᵻnɡræd ; Калининград), until 1946 known as Königsberg (ˈkøːnɪçsbɛʁk; Kyonigsberg; Królewiec), is the largest city and administrative centre of Kaliningrad Oblast, a Russian exclave between Lithuania and Poland. The city sits about west from mainland Russia. The city is situated on the Pregolya River, at the head of the Vistula Lagoon on the Baltic Sea, and is the only ice-free port of Russia and the Baltic states on the Baltic Sea. Its population in 2020 was 489,359, with up to 800,000 residents in the urban agglomeration.
TopologyIn mathematics, topology (from the Greek words τόπος, and λόγος) is concerned with the properties of a geometric object that are preserved under continuous deformations, such as stretching, twisting, crumpling, and bending; that is, without closing holes, opening holes, tearing, gluing, or passing through itself. A topological space is a set endowed with a structure, called a topology, which allows defining continuous deformation of subspaces, and, more generally, all kinds of continuity.
